CN113380916B - Dual-mode uncooled infrared detector thermosensitive layer structure and preparation method thereof - Google Patents

Abstract

The invention provides a dual-mode uncooled infrared detector thermosensitive layer structure and a preparation method thereof. The invention can be used for a dual-mode uncooled infrared detector, and when a scene requiring NETD low, the VOx film is put into operation, and the detector enters a VOx-based infrared detection mode; in a scene with high required response rate, the amorphous germanium-silicon film is put into operation, and the detector enters an amorphous germanium-silicon-based infrared detection mode; when high-quality static infrared scene shooting is required, the VOx film and the amorphous germanium-silicon film are simultaneously put into operation, and the two modes work together; therefore, the invention is suitable for different working scenes, and has wide application range and low cost.

Description

Dual-mode uncooled infrared detector thermosensitive layer structure and preparation method thereof

technical field

The invention belongs to the field of uncooled infrared detectors, and in particular relates to a dual-mode uncooled infrared detector thermosensitive layer structure and a preparation method thereof.

Background technique

The heat-sensitive material part of the uncooled infrared detector mainly uses amorphous germanium silicon, VO _X , etc. The amorphous germanium silicon-based infrared detector has a high responsivity and a high detection rate, which is attributed to the good thermal performance of the amorphous germanium silicon layer (ie The temperature coefficient of resistance is large) and the thermal conductivity is low, but its 1/f noise is relatively large, so the NETD of the device is large. The 1/f noise of VOx-based infrared detectors is small, so the NETD is small. At the same time, VOx has a suitable temperature coefficient of resistance (TCR) and excellent thermal performance, but the responsivity is significantly lower than that of amorphous germanium-silicon-based infrared detectors. In order to meet the needs of infrared detection in different scenarios (such as scenarios requiring a small detector NETD and a scenario requiring a large detector response rate), and infrared detectors have excellent performance in different scenarios, based on this, we propose a dual-mode working Infrared detector, and the design of its heat-sensitive layer structure is given.

Contents of the invention

The purpose of the present invention is to provide a dual-mode uncooled infrared detector heat-sensitive layer structure and its preparation method, aiming to solve the problem that the heat-sensitive layer structure of the existing infrared detector cannot meet the needs of different scenarios of the infrared detector .

The present invention is achieved like this:

On the one hand, the present invention provides a dual-mode uncooled infrared detector heat-sensitive layer structure, including a protective layer and a heat-sensitive thin film layer located above the protective layer, and the heat-sensitive thin film layer includes amorphous silicon germanium arranged on two sides thin film and VOx thin film.

Further, there is a gap between the amorphous silicon germanium thin film and the VOx thin film.

Further, the VOx film is a V ₂ O ₅ film.

Further, the VOx thin film is a vanadium pentoxide thermosensitive thin film with a sandwich structure, including at least two V ₂ O ₅ layers and a carrier concentration increasing layer located between every two adjacent V ₂ O ₅ layers.

Further, the carrier concentration increasing layer is made of graphene composite F ions.

Further, the carrier concentration increasing layer is made of V ₂ O ₃ oxide doped with W ⁶⁺ .

Further, the carrier concentration increasing layer is made of V ₂ O ₃ oxide doped with Ru ⁴⁺ .

On the other hand, the present invention also provides a method for preparing a heat-sensitive layer structure of a dual-mode uncooled infrared detector as described above, comprising the following steps:

(1) Growth of the first protective layer;

(2) A VOx thin film is grown on the first protective layer by PVD method;

(3) Deposit the second protective layer on the VOx thin film by CVD method;

(4) Use an etching machine to etch the VOx film and the second protective layer in some areas;

(5) Deposit a layer of amorphous germanium silicon film on the etched part area by low pressure vapor phase chemical deposition method;

(6) Use an etching machine to etch the designed pattern on the VOx thin film and the amorphous germanium silicon thin film.

Further, the step (2) specifically includes:

Firstly, PVD method is used to deposit a metal vanadium thin film with a thickness of 30-100nm. After the preparation is completed, it is annealed at 500-600°C for 1-2h in an oxygen atmosphere.

Further, the step (5) specifically includes:

Using GeH ₄ and Si ₂ H ₆ mixed gas, the ratio of the flow rate of the two gases is controlled between 0-1.4 sccm, the total flow rate is 5-15 sccm, the pressure is kept at 20-60 Pa, and the temperature is kept at 300-500°C. After completion, anneal at 500-600 degrees Celsius for 1-4 hours.

Compared with the prior art, the present invention has the following beneficial effects:

The heat-sensitive layer structure and preparation method of the dual-mode uncooled infrared detector provided by the present invention, the heat-sensitive film layer includes an amorphous germanium-silicon film and a VOx film arranged on two sides, which can be used for dual-mode uncooled infrared detection In scenarios that require low NETD, such as imaging living organisms, the VOx film is put into operation, and the detector enters the VOx-based infrared detection mode; in scenarios that require high responsivity, such as tracking aircraft, missile exhaust, amorphous germanium silicon film When it is put into operation, the detector enters the amorphous germanium silicon-based infrared detection mode; when high-quality static infrared scene shooting is required, such as nighttime imaging of urban night scenes, the VOx thin film and the amorphous germanium silicon thin film are put into work at the same time, and the two modes work together, that is The images captured by the two detectors are digitally processed, and the images are synthesized into a clearer image through an algorithm. Therefore, the present invention is applicable to different working scenes, has a wide range of applications, and is low in cost.

Description of drawings

Fig. 1 is a schematic diagram of a thermal layer structure of a dual-mode uncooled infrared detector provided by an embodiment of the present invention;

Fig. 2 is a partial structural diagram of a dual-mode uncooled infrared detector provided by an embodiment of the present invention;

Fig. 3 is the structure of the product obtained in step (2) in the preparation method of the heat-sensitive layer structure of a dual-mode uncooled infrared detector provided by the embodiment of the present invention;

Fig. 4 is the structure of the product obtained in step (3) in the preparation method of the heat-sensitive layer structure of a dual-mode uncooled infrared detector provided by the embodiment of the present invention;

Fig. 5 is the product structure obtained in step (4) in the preparation method of a dual-mode uncooled infrared detector heat-sensitive layer structure provided by the embodiment of the present invention;

Fig. 6 is a structure of a product obtained in step (5) of a method for preparing a heat-sensitive layer structure of a dual-mode uncooled infrared detector provided by an embodiment of the present invention.

Description of reference numerals: 1—protective layer/first protective layer, 2—thermosensitive thin film layer, 21—amorphous silicon germanium thin film, 22—thermosensitive thin film, 3—support leg, 4—second protective layer.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1 and Figure 2, the embodiment of the present invention provides a dual-mode uncooled infrared detector heat-sensitive layer structure, including a protective layer 1 and a heat-sensitive thin film layer 2 above the protective layer, the protective layer 1 can Using Si ₃ N ₄ , the heat-sensitive film layer 2 includes an amorphous germanium silicon film 21 and a VOx film 22 arranged on two sides. In this embodiment, the amorphous germanium silicon film 21 and the VOx film 22 are respectively Accounting for half, preferably, there is a gap between the amorphous silicon germanium thin film 21 and the VOx thin film 22 to prevent the influence between the two. As shown in Figure 2, it is a partial structural diagram of the dual-mode uncooled infrared detector applying the heat-sensitive layer structure of this embodiment. In addition to the heat-sensitive layer structure, it also includes some other structures such as supporting legs 3, which are conventional technologies in the art , which will not be repeated here. When the heat-sensitive layer structure of this embodiment is applied to a dual-mode uncooled infrared detector, the VOx film 22 and the amorphous germanium-silicon film 21 can be connected to the detector through different circuits, and the conduction of the circuit can be controlled by a switch The state controls whether the VOx thin film 22 and the amorphous silicon germanium thin film 21 enter the working mode. In scenarios where low NETD is required, such as imaging living organisms, the VOx thin film 22 is put into operation, and the detector enters the VOx-based infrared detection mode; Scenes, such as tracking aircraft and missile tail flames, the amorphous germanium silicon thin film 21 is put into operation, and the detector enters the amorphous germanium silicon based infrared detection mode; when high-quality static infrared scene shooting is required, such as night imaging of city night scenes, the VOx thin film 22 and the amorphous silicon germanium thin film 21 are put into work at the same time, and the two modes work together, that is, digital processing is performed on the pictures captured by the two detectors, and the images are synthesized into a clearer image through an algorithm; therefore, the present invention is applicable to different Working scenarios, a wide range of applications, and low cost.

Preferably, the VOx thin film 22 is a V ₂ O ₅ thin film, which has good thermal sensitivity and high thermal stability. Further preferably, the VOx thin film 22 is a vanadium pentoxide thermosensitive thin film with a sandwich structure, including at least two V ₂ O ₅ layers and an increased carrier concentration between every two adjacent V ₂ O ₅ layers. layer. There may be two or more V ₂ O ₅ layers, and a carrier concentration increasing layer is arranged between every two adjacent V ₂ O ₅ layers to make the carrier concentration more uniform. Increase the carrier concentration of the V ₂ O ₅ thermosensitive film through the carrier concentration increasing layer, significantly reduce the resistance value of the V ₂ O ₅ thermosensitive film at room temperature, and effectively solve the resistance of the V ₂ O ₅ thermosensitive film at room temperature To solve the problem of extremely large and low thermal sensitivity, improve the thermal sensitivity of V ₂ O ₅ thermally sensitive thin film, so that the responsivity increases when it is used as a device; and the thickness ratio of the layer can be increased by adjusting the V ₂ O ₅ layer and the carrier concentration To adjust the resistance, the greater the thickness of the carrier concentration increasing layer, the smaller the thickness of the V ₂ O ₅ layer, the greater the overall carrier concentration of the V ₂ O ₅ thermosensitive film, the smaller the resistance, on the contrary, The smaller the thickness of the carrier concentration increasing layer, the larger the thickness of the V ₂ O ₅ layer, the smaller the overall carrier concentration of the V ₂ O ₅ thermosensitive film, the greater the resistance, which can be adjusted according to different actual needs , easy to adjust, and does not require additional costs.

Further refining the carrier concentration increasing layer, as a first embodiment, the carrier concentration increasing layer is made of graphene composite F ions (Graphene&F ^- ), and the thickness is preferably 10-50 nm. F ^- has a small ion radius, can replace O ^2- in V ₂ O ₅ , and exists in large quantities in the V ₂ O ₅ lattice gap, and the use of Graphene to adsorb F ^- increases the free carrier concentration of the thermally sensitive thin film system, making The resistance value reaches the working value of the circuit, and the Graphene layer is conducive to the horizontal conduction of heat, so the TCR of the VOx film 22 is improved, the thermal sensitivity of the film is also improved, and the response rate of the device will be increased. As a second implementation manner, the material of the carrier concentration increasing layer is V ₂ O ₃ oxide doped with W ⁶⁺ , and the thickness is 3-23 nm. V ₂ O ₃ is a conductor at room temperature, with 0 band gap and high free carrier concentration. W ⁶⁺ ions can further increase the carrier concentration in the film to reduce the resistance of V ₂ O ₅ . As a third implementation manner, the material of the carrier concentration increasing layer is V ₂ O ₃ oxide doped with Ru ⁴⁺ , and the thickness is 3-23 nm. V ₂ O ₃ is a conductor at room temperature, with zero band gap and high free carrier concentration. The special conductor properties of RuO ₂ make it possible to further increase the carrier concentration in the film by doping Ru ⁴⁺ to reduce the resistance of V ₂ O ₅ role.

The embodiment of the present invention also provides a method for preparing the heat-sensitive layer structure of the dual-mode uncooled infrared detector of the above-mentioned embodiment, including the following steps:

(1) growing the first protective layer 1, the first protective layer 1 is made of Si ₃ N ₄ ;

(2) A VOx thin film 22 is grown on the first protective layer 1 by PVD (Physical Vapor Deposition); the thickness and resistance meet the requirements of circuit design, as shown in FIG. 3 ;

(3) Deposit a second protective layer 4 on the VOx thin film 22 by CVD (Chemical Vapor Deposition), and the second protective layer is also made of Si ₃ N ₄ with a thickness of 100-400 nm, as shown in FIG. 4 ;

(4) Use an etching machine to etch the VOx thin film 22 and the second protective layer 4 in a part of the area, as the deposition area of the amorphous silicon germanium thin film 21, as shown in FIG. 5 ;

(5) Deposit a layer of amorphous germanium silicon film 21 in the etched part area by low-pressure vapor-phase chemical deposition method, with a thickness of 30-100nm, as shown in FIG. 6;

(6) Using an etching machine to etch a designed pattern on the VOx film 22 and the amorphous germanium silicon film 21 .

Preferably, the step (2) specifically includes:

Firstly, PVD method is used to deposit a metal vanadium thin film with a thickness of 30-100nm. After the preparation is completed, it is annealed at 500-600°C for 1-2h in an oxygen atmosphere.

Preferably, the step (5) specifically includes:

Using GeH ₄ and Si ₂ H ₆ mixed gas, the ratio of the flow rate of the two gases is controlled between 0-1.4 sccm, the total flow rate is 5-15 sccm, the pressure is kept at 20-60 Pa, and the temperature is kept at 300-500°C. After completion, anneal at 500-600 degrees Celsius for 1-4 hours.

The above method adopts CVD and PVD to realize the preparation of the heat-sensitive layer structure of the dual-mode uncooled infrared detector, which is compatible with the silicon-based semiconductor process, and the preparation method is controllable.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (5)

1. A dual-mode uncooled infrared detector heat-sensitive layer structure, characterized in that: comprise a protective layer and a heat-sensitive film layer positioned above the protective layer, and said heat-sensitive film layer comprises amorphous germanium that is arranged on the left and right sides Silicon thin film and VOx thin film, the VOx thin film is a vanadium pentoxide thermosensitive thin film with a sandwich structure, including at least two layers of V ₂ O ₅ layers and a carrier concentration between each adjacent two layers of V ₂ O ₅ layers The raising layer, the carrier concentration raising layer is made of graphene composite F ions. 2. The heat-sensitive layer structure of the dual-mode uncooled infrared detector according to claim 1, wherein there is a gap between the amorphous silicon germanium thin film and the VOx thin film. 3. A preparation method of the dual-mode uncooled infrared detector thermosensitive layer structure as described in any one of claims 1-2, is characterized in that, comprises the following steps: (1) Growth of the first protective layer; (2) A VOx thin film is grown on the first protective layer by PVD method; (3) Deposit the second protective layer on the VOx thin film by CVD method; (4) Use an etching machine to etch the VOx film and the second protective layer in some areas; (5) Deposit a layer of amorphous germanium silicon film on the etched part area by low pressure vapor phase chemical deposition method; (6) Use an etching machine to etch the designed pattern on the VOx thin film and the amorphous germanium silicon thin film. 4. The method for preparing the heat-sensitive layer structure of the dual-mode uncooled infrared detector according to claim 3, wherein the step (2) specifically comprises: Firstly, PVD method is used to deposit a metal vanadium thin film with a thickness of 30-100nm. After the preparation is completed, it is annealed at 500-600°C for 1-2h in an oxygen atmosphere. 5. The method for preparing the heat-sensitive layer structure of the dual-mode uncooled infrared detector according to claim 3, characterized in that: the step (5) specifically includes: Using GeH ₄ and Si ₂ H ₆ mixed gas, the ratio of the flow rate of the two gases is controlled between 0-1.4 sccm, the total flow rate is 5-15 sccm, the pressure is kept at 20-60 Pa, and the temperature is kept at 300-500°C. After completion, anneal at 500-600 degrees Celsius for 1-4 hours.

Images